| AVS 57th International Symposium & Exhibition | |
| Surface Science | Tuesday Sessions |
| Session SS1-TuM |
| Session: | Catalysis on Metal and Alloy Surfaces |
| Presenter: | H.C. Ham, University of Texas at Austin |
| Authors: | H.C. Ham, University of Texas at Austin J.A. Stephens, University of Texas at Austin G.S. Hwang, University of Texas at Austin |
| Correspondent: | Click to Email |
Gold-based bimetallic alloys have been found to significantly increase catalytic efficiency, compared to their monometallic counterparts in various reactions including low temperature oxidation of CO, direct synthesis of H2O2 from H2 and O2, and production of vinyl acetate monomers. Recent experimental and theoretical studies have suggested that the reactivity of bimetallic catalysts can be governed by creation of unique mixed-metal surface sites (ensemble effect) and/or electronic structure change by metal-metal interactions (ligand effect), while mechanisms underlying the alloying effect still remain unclear. In this talk, we will present the recent results of our first principles calculations on the mechanisms of CO oxidation and oxygen reduction reaction (ORR) on AuPd and AuPt alloy surfaces. Using periodic density functional theory calculations, we find that the rate of CO oxidation can be a strong function of Pd/Pt ensembles, while the ensemble effect is likely to be more important in the AuPd case. In addition, we find that ORR tends to be promoted on PdAu alloys, compared to the pure Pd case. This work provides valuable hints on the importance of the interplay of the ensemble and ligand effects in determining the catalytic activity of Au-based bimetallic catalysts particularly toward CO oxidation and ORR.